Rosseland, Planck, and stellar mean opacities (from left to right) as a function of temperature for grains with water abundances of 10, 30, 50, and 70%. We calculated these opacities with RADMC-3D for a dust-to-gas ratio of 1%. The solid lines correspond to a grain size of 1 μm, and the dashed lines correspond to a size of 1 mm. The water-ice line transition (vertical grey line) is located at (170 ± 10) K, causing a transition in opacity due to the evaporation and condensation of dust grains.